Information reproduction head apparatus and information recording/reproduction system

Abstract

The present invention provides a yoke-type information reproduction head apparatus 100 having a magnetic sensor block 3 provided on the substrate 1 via a non-magnetic insulation layer 2. The magnetic sensor 3 includes a ferromagnetic tunnel junction element 5 which is sandwiched between an upper electrode block 6 and a lower electrode block 7 and which is connected to a magnetic domain control bias layer 8. This enables to obtain preferable S/N and bit error rate with reduced waveform noise. This invention provides a yoke-type information reproduction head having both of the characteristics of the front yoke 4 - 1 as a magnetic path and a lower electrode 7 as an electric path.

What is claimed is:  
     
         1 . A yoke type information reproduction head apparatus comprising a magnetic sensor block placed on a non-magnetic insulation layer provided on a substrate, the magnetic sensor being connected to a magnetic pole and including a ferromagnetic tunnel junction element sandwiched by an upper electrode block and a lower electrode block, 
 wherein the tunnel junction element is in junction with a magnetic domain control bias layer.    
     
     
         2 . A yoke type information reproduction head apparatus as claimed in  claim 1 , wherein the bias layer is in junction a with free magnetic layer constituting a tunnel junction element.  
     
     
         3 . A yoke type information reproduction head apparatus as claimed  claim 1 , wherein the bias layer is at least partially overlaid on the free magnetic layer.  
     
     
         4 . A yoke type information reproduction head apparatus as claimed  claim 2 , wherein the bias layer is at least partially overlaid on the free magnetic layer.  
     
     
         5 . A yoke type information reproduction head apparatus as claimed  claim 1 , wherein the bias layer has a rectangular shape and one side of the rectangular shape is in junction with the end portion of the free magnetic layer or a part of the rectangular shape is overlaid on the end portion of the free magnetic layer.  
     
     
         6 . A yoke type information reproduction head apparatus as claimed  claim 2 , wherein the bias layer has a rectangular shape and one side of the rectangular shape is in junction with the end portion of the free magnetic layer or a part of the rectangular shape is overlaid on the end portion of the free magnetic layer.  
     
     
         7 . A yoke type information reproduction head apparatus as claimed  claim 1 , wherein the bias layer is arranged in a direction vertically intersecting the magnetic pole.  
     
     
         8 . A yoke type information reproduction head apparatus as claimed  claim 2 , wherein the bias layer is arranged in a direction vertically intersecting the magnetic pole.  
     
     
         9 . A yoke type information reproduction head apparatus as claimed in  claim 1 , wherein the non-magnetic insulation layer is buried in the substrate.  
     
     
         10 . A yoke type information reproduction head apparatus as claimed in  claim 1 , wherein the magnetic pole is connected to at least one of the upper electrode block and the lower electrode block connected to the tunnel junction element.  
     
     
         11 . A yoke type information reproduction head apparatus as claimed in  claim 10 , wherein the magnetic pole is constituted by a first magnetic pole and a second magnetic pole located oppositely with respect to the tunnel junction element and the first magnetic pole is arranged at the side where a medium is present.  
     
     
         12 . A yoke type information reproduction head apparatus as claimed in  claim 1 , wherein the bias layer is made from a ferromagnetic material or hard magnetic material.  
     
     
         13 . An information recording reproduction system comprising: 
 a magnetic storage medium having a plurality of tracks for recording information;    a magnetic recording apparatus for storing the information onto the magnetic storage medium;    the information reproduction head apparatus described in  claim 1;  and    an actuator connected to the magnetic recording apparatus and to the information reproduction head apparatus, for moving the magnetic recording apparatus and the information reproduction head to a selected one of tracks of the magnetic recording medium.    
     
     
         14 . A yoke type information reproduction head apparatus comprising a magnetic sensor block placed on a non-magnetic insulation layer provided on a substrate, the magnetic sensor being connected to a magnetic pole and including a ferromagnetic tunnel junction element sandwiched by an upper electrode block and a lower electrode block, 
 wherein the apparatus includes a front yoke block and a rear yoke block arranged at the opposing positions with respect to the tunnel junction element, the front yoke being located at the side of the tunnel junction element where a medium is present    
     
     
         15 . A yoke type information reproduction head apparatus as claimed in  claim 14 , wherein at least a portion of the front yoke block is overlaid over at least a portion of the lower magnetic pole via the tunnel junction element.  
     
     
         16 . A yoke type information reproduction head apparatus as claimed in  claim 14 , wherein the front yoke block has an end portion in abutment with an end portion of the tunnel junction element.  
     
     
         17 . A yoke type information reproduction head apparatus as claimed in  claim 15 , wherein the front yoke block has an end portion in abutment with an end portion of the tunnel junction element.  
     
     
         18 . A yoke type information reproduction head apparatus as claimed in  claim 16 , wherein the junction surface between the front yoke block and the tunnel junction element has a tapered shape.  
     
     
         19 . A yoke type information reproduction head apparatus as claimed in  claim 17 , wherein the junction surface between the front yoke block and the tunnel junction element has a tapered shape.  
     
     
         20 . A yoke type information reproduction head apparatus as claimed in  claim 14 , wherein the end portion of the front yoke block is engaged with the end portion of the tunnel junction element.  
     
     
         21 . A yoke type information reproduction head apparatus as claimed in  claim 14 , wherein the bias layer is formed in a direction orthogonally intersecting the yoke block.  
     
     
         22 . An information recording reproduction system comprising: 
 a magnetic storage medium having a plurality of tracks for recording information;    a magnetic recording apparatus for storing the information onto the magnetic storage medium;    the information reproduction head apparatus described in claim  14 ; and    an actuator connected to the magnetic recording apparatus and to the information reproduction head apparatus, for moving the magnetic recording apparatus and the information reproduction head to a selected one of tracks of the magnetic recording medium.